Cholesteryl ester transfer protein (CETP), also called plasma lipid transfer protein, is a plasma protein that facilitates the transport of cholesteryl esters and triglycerides between the lipoproteins. It collects triglycerides from very low-density (VLDL) or low-density lipoproteins (LDL) and exchanges them for cholesteryl esters from high-density lipoproteins (HDL), and vice versa. Most of the time, however, CETP does a homoexchange, trading a triglyceride for a triglyceride or a cholesteryl ester for a cholesteryl ester.

Rare mutations leading to increased function of CETP have been linked to accelerated atherosclerosis. In contrast, a polymorphism (I405V) of the CETP gene leading to lower serum levels has also been linked to exceptional longevity